The present invention relates to fluid brake systems for vehicles. More particularly, the invention concerns the integration of anti-lock braking control into a vehicle's fluid brake system utilizing one solenoid per wheel.
Conventional vehicle fluid brake systems are characterized by providing the ability for effective wheel braking in response to manual application of force to a brake pedal actuator. It is known to adapt conventional vehicle fluid brake systems to automatic control mechanisms which intervene in the event of certain conditions and provide advanced braking functions. One such mechanism, an anti-lock braking system (ABS), generally represents a combination of hydraulic and electric controls.
A typical ABS system inhibits the vehicle's wheel brake from locking up by releasing the applied fluid pressure when an incipient wheel lock-up condition is sensed. After release of the fluid pressure wheel deceleration ceases and the wheel begins accelerating towards vehicle speed. When the wheel speed has substantially recovered, braking fluid pressure may be reapplied. The re-application of fluid pressure generally results in the wheel again approaching lock up and the cycle is repeated.
The art has proposed that ABS functions can be provided by employing several different mechanisms. The problem posed in developing an effective ABS braking system is to provide optimum operation considering system response, adaptability and efficiency while concurrently avoiding unnecessary complexity and cost. This presents a significant challenge in the development of vehicle braking systems utilizing ABS.